[BUG] Claude Desktop v1.1.4173 fails to create BrowserWindow — @formatjs/intl unhandled rejection blocks window init (x64, Windows 11 26200)

Preflight Checklist

• [x] I have searched existing issues — multiple reports exist (#28461, #28650, #28271, #28304, #28353, #28395, #28871) but none include root cause analysis
• [x] This is a single bug report
• [x] Using latest version (1.1.4173 is the broken version)

What's Wrong

Claude Desktop v1.1.4173 starts processes but never creates a BrowserWindow. The main process runs indefinitely (performing periodic growthbook refreshes and project detection scans) but no window is ever rendered. This is a 100% reproducible regression from v1.1.4088.

Root Cause Analysis

The @formatjs/intl unhandled promise rejection fires during app initialization, before the window creation code path:

Error: [@formatjs/intl] An `id` must be provided to format a message.
    at nZe (app.asar\.vite\build\index.js:83:2748)
    at Sae (app.asar\.vite\build\index.js:83:4203)
    at WOt (app.asar\.vite\build\index.js:705:12468)
    at RDe (app.asar\.vite\build\index.js:705:14365)
    at Hd (app.asar\.vite\build\index.js:705:15535)
    at EventEmitter.<anonymous> (app.asar\.vite\build\index.js:1234:79020)

This error is caught by Sentry but causes the initialization pipeline to abort silently before reaching window creation.

Evidence from main.log

Working v1.1.4088 initialization sequence:

Starting app { appVersion: '1.1.4088' }
[CCD] Initialized
[IdleManager] Initialized
[office-addin] Module loaded
NotificationService initialized          ← 4173 NEVER reaches this
App is installed, enabling auto-updates  ← 4173 NEVER reaches this
[Chrome Extension MCP] ...
[growthbook] loaded features
[ScheduledTasks] Reset                   ← 4173 NEVER reaches this
[Spaces] Reset                           ← 4173 NEVER reaches this
Loaded persisted sessions                ← 4173 NEVER reaches this
Trying to load oauth token cache         ← 4173 NEVER reaches this
[oauth] loaded token cache               ← 4173 NEVER reaches this

Broken v1.1.4173 initialization sequence:

Starting app { appVersion: '1.1.4173' }
Sentry caught: @formatjs/intl error     ← ERROR
Sentry caught: @formatjs/intl error     ← ERROR (fires twice)
[CCD] Initialized
[IdleManager] Initialized
[office-addin] Module loaded
[Chrome Extension MCP] ...
[growthbook] loaded features
desktop_windows_elevation_detected
desktop_project_detection_completed
[EventLogging] Flushing events
                                         ← DEAD. No more init. No window.

The process stays alive doing periodic project detection every 30 minutes, but the window is never created.

What was tested (all failed on 4173):

• Clean cache clear (GPUCache, DawnGraphiteCache, Session Storage, Local Storage, IndexedDB)
• Window state reset (moved to x:100 y:100)
• Full config.json deletion (forces fresh oauth)
• --disable-gpu flag
• --disable-gpu --disable-software-rasterizer --disable-gpu-compositing
• --no-sandbox
• Running v4088 exe directly → WORKS ✓

Workaround

Run the previous version directly:

"%LOCALAPPDATA%\AnthropicClaude\app-1.1.4088\claude.exe"

Block auto-update by renaming the Squirrel updater:

ren "%LOCALAPPDATA%\AnthropicClaude\Update.exe" "Update.exe.disabled"

Environment

• Platform: Windows 11 Pro 10.0.26200 (x64)
• CPU: AMD Ryzen 9 9900X 12-Core
• RAM: 64GB
• Broken version: 1.1.4173 (commit 12766c56e46a0f6bf202bfa397fceafe4468d7de)
• Last working version: 1.1.4088 (commit 7e63fdb935ef758b2356a3d040ccd9176414cac7)
• Node: 24.13.0
• System locale: en-US (system), en-IN (user culture) — may be relevant to formatjs

Is this a regression?

Yes. v1.1.4088 works perfectly.

Note

This also affects ARM64 (#28461) and likely all Windows users on v1.1.4173. The existing reports (#28650, #28271, #28304, #28353, #28395, #28871) contain the same symptoms but have been tagged invalid despite being legitimate.